Francis’s document, made up of 246 paragraphs, is unusual because it is aimed not just at the world’s Roman Catholics but at ‘every person who inhabits this planet’. He says global warming is the earth’s way of ‘protesting for the wrong that we are doing to her’ and humanity’s belief that ‘we were [the earth’s] owners and dominators, authorised to loot her’. He makes clear his belief that climate change is largely caused by human activity, and calls for different lifestyles and reduced energy consumption to prevent ‘the unprecedented destruction of the ecosystem’.

He makes several references to transport, mostly as part of a number of environmental issues, but a couple of times specifically. He praises investments already made in ‘means of production and transportation which consume less energy and require fewer raw materials’. In talking about ‘the disproportionate and unruly growth of many cities’ he cites ‘poor transportation, and visual pollution and noise’ as part of the reason cities have become unhealthy places to live. And in a long paragraph about environmental education and ‘ecological citizenship’, Francis talks about encouraging ‘a nobility in the duty to care for creation through little daily actions’ and includes in such actions ‘using public transport or car-pooling’.

His biggest reference to transport comes in a paragraph about quality of life. He says systems of transport ‘are often a source of much suffering for those who use them. Many cars, used by one or more people, circulate in cities, causing traffic congestion, raising the level of pollution, and consuming enormous quantities of non-renewable energy. This makes it necessary to build more roads and parking areas which spoil the urban landscape. Many specialists agree on the need to give priority to public transportation. Yet some measures needed will not prove easily acceptable to society unless substantial improvements are made in the systems themselves.’

Although the encyclical calls for a discussion, Francis is very critical of carbon trading. ‘The strategy of buying and selling “carbon credits” can lead to a new form of speculation which would not help reduce the emission of polluting gases worldwide,’ he writes. ‘This system seems to provide a quick and easy solution under the guise of a certain commitment to the environment, but in no way does it allow for the radical change which present circumstances require. Rather, it may simply become a ploy which permits maintaining the excessive consumption of some companies and sectors.’

In a separate development, a group of international health experts brought together by the British medical magazine The Lancet say climate change is threatening to undo 50 years of progress in global health.

The Lancet commission on health and climate change has produced a report saying tackling climate change could be the greatest global health opportunity of the 21^st century. In a departure from the warnings of catastrophe, the commission says the potential exists for a number of ‘no regret’ actions which can be aimed at tackling both climate change and threats to human health, although its general assumption is not about preventing climate change but that such change will happen and nations and blocs will have to adapt to it.

It makes 10 recommendations for the world’s governments, among them increasing funding for climate-resilient health systems, rapidly phasing out coal from the global energy mix, encouraging a transition to cities that encourage healthy and environmental lifestyles with ‘active transport’ (walking and cycling), establishing an international carbon pricing mechanism, and working towards a low-carbon global economy.

One of the commission’s co-chairs described the current situation as ‘a medical emergency’ and that failure to act now means ‘the game could be over’.